A Multimodal Critical Discourse Analysis On Public Service Advertising

Critical discourse analysis(CDA) is not only a kind of theory but also a kind of method to figure out the relationship between language and power relation. It has become an independent field through years of development. However, research on CDA is restricted to the language mode, which mainly focuses on the language system and the semantic structure as well as the relations between the social culture and psychological cognition but neglects the forms of other semiotics such as image and color. In the 1980 s and 1990 s, with the development of the multimodal discourse analysis, many scholars have been attracted by the functions of the multimodal discourse analysis in revealing the power and ideology. It is not until 2012 that Machin and Mayr have come up with the definition of multimodal critical discourse analysis(MCDA). MCDA coins ?multimodal? with CDA and especially pays attention to combing language and visual semiotics, providing theoretical foundation and methodology enlightenment for explaining the power relation and ideology.Public service advertisements(PSAs) are messages in the public interest disseminated by government, public institutions, enterprises and media with the objective of serving the public. They are a kind of institutional discourse. As institutional discourse, PSAs are designed by the designer trying to change the receiver?s thoughts, ideas and behaviors. They seem to convey information to the audience neutrally, but they actually imply some ideology by adopting language and non-language strategies in PSAs. In this sense, PSAs belong to multimodal discourse by conveying the social responsibility, ethics and values through the interaction of both the language and image modes. Moreover, PSAs are different from commercial advertisements in that the ideology and power relation in PSAs seem to be neutral and concealed compared with the strong commercial intensions in persuading people to buy products. Thus, MCDA helps uncover and reveal the ideology and power relation in PSAs and make up for the shortcomings of paying less attention to the non-language semiotics. What?s more, it also plays an important role in deconstructing media discourse as well as institutional discourse by adopting the combination of both language and image modes.As for this, the thesis chooses PSAs from the official website of American Ad Council and adopts a possible MCDA model for the interaction between language and image modes based on Halliday?s systemic functional grammar and Leeuwen?s visual grammar to systematically do research on revealing the ideology and power relation in PSAs. It discusses the ads from the aspect of language mode and image mode as well as the interactions between them to investigate the realization of ideology and power relation. So the thesis tries to discuss the following questions:1) In PSAs, what are the features of language mode?2) In PSAs, what are the features of image mode?3) In PSAs, how do language mode and image mode interact with each other in meaning creating?Based on the research questions, the thesis builds a corpus by choosing 80 static PSAs from the official website of American Ad Council and adopts both qualitative and quantitative methods to discuss the meaning construction in language mode and image modes. The thesis gets the following conclusions:1) As for the language mode, the lexical density is high in PSAs which reflects the nominalization in the PSAs. Nominalization can fuzzify what the designer wants to say at the first place and replaces verb processes with a noun construction, obscuring the agency and responsibility for an action. This demonstrates that the institutions try to construct their own textual meanings based on their intensions. Hence the power control of the discourse is revealed and presented in PSAs. And with regard to sentences, the imperative sentences and declarative sentences in the system are quoted more to convey the mood and among which the imperative sentences represent the powerful control and declarative sentences contain something authoritative. Compelled by the powerful control and authoritative stir, the audience unconsciously accepts the intensions and targets the PSAs are trying to convey;2) In the image mode, the close shot, the eye-level angle and the close personal distance all show the strategy of shortening the distance between the represented participant and viewer. They lowered people?s psychological guard and unconsciously make influence on the audience and put the ideas on their thoughts;3) In combing the two modes, language and image have a close relation with each other in the PSAs. The interaction between language and image is realized by applying the rhetoric devices including metaphor, metonymy, synecdoche and irony. Metaphor and visual metaphor, metonymy and visual metonymy, synecdoche and visual synecdoche and irony and visual irony interact with each other to provide harmonious language ecology for the audience. On the one hand, the imagination stirred by language can be realized through visual rhetoric devices. On the other hand, visual rhetoric devices help reiterate the language rhetoric devices. Obviously, by combing the two modes, the creation of meaning is more powerful and convincible.The research results further proves the powerful explanation of MCDA and provides a distinguished guiding role in designing and disseminating media discourse.